Our current data suggests that blood vessel alterations and collagen deposition in scleroderma is preceded or accompanied by a tissue cellular reaction involving lymphocytes, plasma cells and macrophages. Lymphocytes from normal and scleroderma patients will be stimulated with phytohemagglutinin-P and the supernatant containing the lympholines will be tested "in vitro" on fibroblast cultures for its possible effect on collagen synthesis. 14C proline will be added to normal and scleroderma fibroblast cultures in the presence and absence of lymphokines. Collagen synthesis will be estimated by measuring the conversion of 14C proline to 14C hydroxyproline. In addition, lympholines from stimulated scleroderma lymphocytes will be tested for angiogenic activity using the chorioallantoid membrane of chick embryos. Neoformation of blood vessels and endothelial cell proliferation will be studied. BIBLIOGRAPHIC REFERENCES: Bashey, R.I., Perlish, J.S. and Fleischmajer, R.: Collagen synthesis and glycosylation by cultured normal and scleroderma dermal fibroblasts. Fed. Proc. 35:679, 1976 (Abs). Fleischmajer, R. and Perlish, J. S.: 3H-thymidine labeling of endothelial cells in scleroderma. Fed. Proc. 35:680, 1976 (Abs).